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use std::ptr::{drop_in_place, NonNull};
use crate::traits::Class;
/// An owning wrapper around a pointer. PhysX object creation returns pointers
/// which in normal Rust would be a Box, but Box cannot be used here because it
/// has specific allocation requirements that the C++ code does not fulfill.
#[repr(transparent)]
pub struct Owner<T> {
ptr: NonNull<T>,
}
impl<T> Owner<T> {
/// Create a new owner from a raw pointer. Use the `from_raw` method on the type!
///
/// # Safety
///
/// Only one of these may be constructed per pointer. In particular,
/// this must not be called on a pointer attained via Class::as_mut_ptr. The
/// intended pattern is to wrap the raw FFI constructors in this call, so that
/// the amount of time spent dealing with raw pointers is as little as possible.
pub(crate) unsafe fn from_raw(ptr: *mut T) -> Option<Self> {
Some(Self {
ptr: NonNull::new(ptr)?,
})
}
/// Consumes the Owner without calling Drop and returns the raw pointer it was wrapping.
#[allow(clippy::mem_forget)]
pub fn into_ptr<S>(mut self) -> *mut S
where
T: Class<S>,
{
let ptr = self.as_mut_ptr();
std::mem::forget(self);
ptr
}
}
unsafe impl<T, S> Class<S> for Owner<T>
where
T: Class<S>,
{
fn as_ptr(&self) -> *const S {
self.as_ref().as_ptr()
}
fn as_mut_ptr(&mut self) -> *mut S {
self.as_mut().as_mut_ptr()
}
}
unsafe impl<T: Send> Send for Owner<T> {}
unsafe impl<T: Sync> Sync for Owner<T> {}
impl<T> Drop for Owner<T> {
fn drop(&mut self) {
unsafe { drop_in_place(self.ptr.as_ptr()) }
}
}
impl<T> AsRef<T> for Owner<T> {
fn as_ref(&self) -> &T {
unsafe { self.ptr.as_ref() }
}
}
impl<T> AsMut<T> for Owner<T> {
fn as_mut(&mut self) -> &mut T {
unsafe { self.ptr.as_mut() }
}
}
impl<T> std::ops::Deref for Owner<T> {
type Target = T;
fn deref(&self) -> &Self::Target {
self.as_ref()
}
}
impl<T> std::ops::DerefMut for Owner<T> {
fn deref_mut(&mut self) -> &mut Self::Target {
self.as_mut()
}
}